Heavy flavour at HERA as probe of QCD

The author considers production of heavy flavours, specifically of charm and bottom quarks, at HERA. He does this from the point of view of asking what one can learn about QCD. The importance of heavy flavour production in e-p scattering is that it is a process that in lowest-order perturbation theory for the hard scattering is gluon induced. The quark-induced contribution only comes from higher-order corrections in alpha _S. This is not the case for ordinary deeply inelastic scattering nor for production of heavy flavours or of jets in hadron-hadron collisions. Thus heavy flavour production at HERA will provide an important tool to measure the distribution of gluons in the proton. The order alpha _S² corrections to heavy quark production have been calculated, at least in the photoproduction case, Q=0.